An updated overview on the development of new photosensitizers for anticancer photodynamic therapy

Abstract

Photodynamic therapy (PDT), based on the photoactivation of photosensitizers (PSs), has become a well-studied therapy for cancer. Photofrin®, belonging to the first generation of PS, is still widely used for the treatment of different kinds of cancers; however, it has several drawbacks that significantly limit its general clinical use. Consequently, there has been extensive research on the design of PS molecules with optimized pharmaceutical properties, with aiming of overcoming the disadvantages of traditional PS, such as poor chemical purity, long half-life, excessive accumulation into the skin, and low attenuation coefficients. The rational design of novel PS with desirable properties has attracted considerable research in the pharmaceutical field. This review presents an overview on the classical photosensitizers and the most significant recent advances in the development of PS with regard to their potential application in oncology.

Photophysicochemical Properties and In Vitro Phototherapeutic Effects of Iodoquinoline- and Benzothiazole-Derived Unsymmetrical Squaraine Cyanine Dyes

“…Although some PDT photosensitizers are already commercially available, mostly derived from porphyrins, these light-sensitive molecules have the disadvantage of being slowly eliminated from the body, causing skin photosensitivity [8,39]. Thus, several research studies have recently reported the discovery of new compounds, such as cyanines [40], squaraines [24], chlorins [41] or phthalocyanines [42] which, by appropriate structural modifications, can ideally override the gaps of first-generation photosensitizers [43].…”

An Activatable Photosensitizer Targeting Human NAD(P)H: Quinone Oxidoreductase 1

“…The 3‐fold difference in Φ Δ suggests that the efficiency of PN to undergo intersystem crossing is reduced when coupled to quinone. We also note that both PN and 1 demonstrate good photostability upon 415 nm irradiation for up to 15 minutes (12 mW cm −2 , 10.8 J cm −2 ) suggesting that neither compound undergoes photodegradation under these conditions (Figure S4, Supporting Information) …”

“…The 3-fold differencei nF D suggests that the efficiency of PN to undergo intersystem crossing is reduced when coupled to quinone.W ea lso note that both PN and 1 demonstrate good photostability upon 415 nm irradiation for up to 15 minutes (12 mW cm À2 ,1 0.8 Jcm À2 )s uggesting that neither compound undergoes photodegradation under these conditions ( Figure S4, Supporting Information). [48] To prove that the PN in 1 is quenched due to intramolecular PeT quenching, we performed computational experiments. We predicted that PN may be the donor in this interaction because its highly conjugated system makes it more electron-rich relative to Q3PA.H ybrid HF-DFT (Hartree-Fock-density functional theory) calculations predicted that the energy of the HOMO and LUMO for PN are À570.57 kcal mol À1 and À210.45kcal mol À1 ,r espectively,w hile the HOMO andL UMO energies for Q3PAw ere predicted to be À654.89 kcal mol À1 and À257.86kcal mol À1 ,r espectively (Figure 2a nd Figure S5, Supporting Information).…”

Progress of nanotechnology for phototherapy: Fundamentals and applications

“…Therefore, the available IR-light response PSs are important. An updated overview on the development of new photosensitizers for anticancer photodynamic therapy was reported by Zhang et al, [30]. More clinical studies of the efficacy of PDT and PTT using various nanoparticles have been reported [31][32][33][34][35][36][37][38][39].…”